The transmission of light through thin fibers of which fiber glass or plastics has resulted in a variety of instruments for the visualization of otherwise inaccessible organs and tissues inside the human body. Such instruments are broadly referred to as endoscopes and have been useful in the diagnosis and treatment of, for example, gastro intestinal and respiratory diseases.
Fiberoptic endoscopes were first introduced about thirty years ago. Although they have gained wide acceptance where flexibility is required, medical personnel still prefer to use rod lenses or other alternatives. The reason being that they are annoyed by the fixed mosaic structure of a fiberoptic image. Also in most applications, the resolution of present fiberoptic endoscopes is generally inferior to other alternatives.
It is known in the art to scan with fiberoptics. If a multifiber is rotated, a concentric noise pattern is superimposed on the image. If the multifiber is not moved, a mosaic-like noise pattern is superimposed on the image.
In my issued U.S. Pat. No. 5,074,642, which patent is hereby incorporated by reference in its entirety into this disclosure, a multifiber endoscope was disclosed with much improved resolution for a given diameter and which partially eliminated the fixed pattern noise typical of fiber endoscopes. However, I have found that even with rotational scanning there is still a residual fixed pattern streakiness comprising concentric circles even though the individual fibers themselves are no longer visible. Also, a small area near the axis of rotation has a very pronounced fixed pattern noise.
My issued U.S. Pat. No. 5,133,035, which patent is hereby incorporated by reference in its entirety into this disclosure, embodied a multiple-scanning multifiber assembly which substantially reduced or eliminated the noise inherent in prior art multifiber endoscopes. The multiple scanning comprised either a rotary and a chromatic scan or two rotary scans.
In the present invention, it has been discovered that a clear image is produced without a rotational scan of the multifiber. That is, both the multifiber and the prism and/or grating remain fixed.